Speed vs BC?

Discussion in 'Reloading' started by Albertaguide, Aug 1, 2013.

  1. Albertaguide

    Albertaguide Active Member

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    I was loading rounds for my 243win. Disappointed in her apparent distaste for 107 Amax. But pleased with the performance of 90gr Bergers. It occurred to me if I shoot lighter bullets faster the less time gravity has to work on them. I primarily use the quarter bore for coyotes from muzzle to 5-600 yds. No complaints or issues with my pet loads (75gr amax and 90gr bergers) just curious when does BC trump velocity?
     
  2. Lefty7mmstw

    Lefty7mmstw Well-Known Member

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    It depends on your use for the cartridge.
    If you are a dialer your primary objective is to get a lot of energy on target accurately at long range and the bigger and sleaker the pill, the better.
    If you will be shooting offhand and/or shooting moving game time of flite and drop must also be considered. I personally don't like my time of flite to be any longer than necessary to get a pill downrange to put a hole through my target. I shoot big enough rounds that better drop and shorter time of flite offsets a harder hit rather well.
     

  3. roninflag

    roninflag Well-Known Member

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    Alberta- you need to run the numbers for your individual loads. the 140 berger out of my 7mm is faster and flatter than the 168 for quite a ways. roninflag
     
  4. Mikecr

    Mikecr Well-Known Member

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    You have to run the numbers through ballistic software, as there is no rule of thumb.
     
  5. winmag

    winmag Well-Known Member

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    I'm a lil confused by the post

    First anything over about 100-105gr out of a .243 needs a fast twist bbl to stabilize from what I've heard.
    Second, a "quarterbore" is .25 cal not .243......

    My personal opinion on "most but not all" rifle cartridges is it doesn't make a whole lot of difference out to 4-500yds speed vs BC. But the farther out you go, BC becomes king no matter what cartridge.
     
  6. Albertaguide

    Albertaguide Active Member

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    Pretty much what I do now. Heavy for caliber in my target loads and faster medium for big game, light weight for varmints. And yes I run all my loads thru AE ballistic and then compare to the findings to real world trigger time. My question was more out of curiosity than a request for advice and I know quarter bore is .257, late nights early mornings and 14 hour days takes a toll. (no I don't reload while tired)
     
  7. lisagrantb

    lisagrantb Well-Known Member

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    like the others said, run the numbers on your round. For me I almost always run heavy. The reason is I don't have as much of a problem with hitting what i'm shooting at from the vertical standpoint, it's the windage and in the wind game BC is always the best way to go.
     
  8. wisdeerkiller

    wisdeerkiller Active Member

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    My personal opinion on "most but not all" rifle cartridges is it doesn't make a whole lot of difference out to 4-500yds speed vs BC. But the farther out you go, BC becomes king no matter what cartridge.[/QUOTE]


    +1 ENOUGH SAID!
     
  9. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Alberta,

    Do you have an 8" twist or better? If you don't that's probably why your rifle doesn't like the 107 Amax. If you do, have you thought about the 105 Hybrid or 107 MatchKing?

    As others have said, you just have to run the numbers in a ballistic calc. The diff will be very small to 600 yds
     
  10. idaho elk hunter

    idaho elk hunter Well-Known Member

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    I will quote one of the greatest cartridge and firearms designers of the 20th century... " Velocity kills" ROY WEATHERBY...
     
  11. MontanaRifleman

    MontanaRifleman Well-Known Member

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    One of the greatest marketers also.... :)

    Ballistic calculators don't lie